Carbon arc welding apparatus



April 1953 P. ANDERSON 2,636,147

CARBON ARC WELDING APPARATUS Filed Jan. 7, 1950 2 SHEET$-SHEET l 7 4 Hal.

I null AT TORNEYS April 21, 1953 P. ANDERSON 2,636,147 CARBON ARC WELDING APPARATUS Filed Jan. 7, 1950 2 SHEETS-SHEET 2 VMICRO SWITCH A INVENTOR. Perry Anderson 441m? Aid,

ATTORNEYS.

Patented Apr. 21, 1953 CARBON ARC WELDING APPARATUS Perry Anderson, Milwaukee, Wis, assignor to A. O. Smith Corporation, Milwaukee, Wis'., a

corporation of New York Application January 7, 1950, Serial. No. 137,464

19 Claims. 1

This invention relates to carbon arc welding apparatus.

An object of the invention is to provide a carbon arc welding apparatus which will easily and rapidly make welds in relatively inaccessible recesses.

Another object of the invention is to provide a carbon arc welding device which automatically feeds the carbon electrode after it has burned or broken off.

Another object is to provide a welding apparatus with which a number of welds may be made with uniform arc length and uniform weld period.

Another object of the invention is to provide a carbon arc welding apparatus which automatically rotates the electrode to promote uniformity of burning.

The apparatus, in general, comprises an electrode holding barrel mounted on a back plate for vertical movement with relation thereto, a solenoid and linkage arranged on the back plate to actuate the barrel and electrode, and an air cylinder and piston disposed beneath the back plate to vertically move the same along a pair of guide tracks. A relay system, actuated when the back plate is in its lower position, automatically controls the solenoid, as well as the contactor in the welding current circuit, so that the electrode is operated to strike the arc and a weld of short duration is made. Ratchet mechanisms are provided both to feed the electrode, and thus maintain a uniform arc length, and to intermittently rotate the electrode to promote uniformity of burning.

Other objects and advantages will be set forth more fully in the following description of an embodiment of the invention as illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a front elevation of the apparatus with portions broken away to show details of structure;

Fig. 2 is a horizontal section taken at line 2--2 of Fig. 1;

Fig. 3 is a top view of the feeding ratchet;

Fig. 4 is a side elevation of the feeding ratchet including the limiting set screws;

Fig. 5 is a top detail view of the holding ratchet and the yoke which supports the electrode holding barrel;

Fig. 6 is a vertical section of the holding ratchet taken along line 66 of Fig. 5;

Fig. 7 is a horizontal section of the brush which feeds current into the electrode holding barrel;

Fig. 8 is a top view of the'rotating ratchet with 2 portions broken away to show structural details;

Fig. 9 is a vertical section of the lower end of the electrode holding barrel;

F 10- is a horizontal section taken at line iii-40 of Fig. 9;

Fig. 11 is a detail view of the stop and micro switch box of Fig. 1; and

Fig. 12 is a schematic wiring diagram of the electrical circuits of the apparatus.

Referring to the drawings, the structure may include a rigidly constructed cabinet I the upper surface of which is adapted with bolts or the like to support a suitable worktable 2 and a pair of upwardly projecting guides 3. The worktable 2 has positioned thereon an article to be welded, for example, a nut 4 to be fused to a bolt 5 which extends inwardly from the closed end of a hollow piston 6.

The guides 3, illustrated as a pair of angle irons connected at their upper ends by a brace I, serve as tracks for a plurality of grooved wheels 8 which are mounted at each corner of a vertical back plate 9. The back plate 9 is thus free to move vertically but is restrained by the guides 3 from rotational, vibratory, or other undesirable movement.

The back plate 9 may be elevated or lowered by means of an air cylinder l0 and piston H, both of which are disposed in the cabinet I with the air cylinder 10 rigidly secured to the lower end thereof. The piston II is connected to the back plate 9 by a bar 12 which extends vertically through an aperture in the upper surface of the cabinet I and is preferably welded to the objects which it connects.

The flow of air from a compressed air source to the air cylinder 10 is governed by a two-position valve l3 in an air hose 1 4. The valve l3 may be secured in any convenient place, such as the top surface of cabinet I. When the valve I3 is turned to its weld position, the air is released from the cylinder [0 and the back plate 9 falls towards the article to be welded. The turning of the valve 13 to its off position causes compressed air to flow into the cylinder l0 and thereby elevate piston H and back plate 9.

Although the valve !3 is shown in the drawings as being of the manually operated type, a suitable control could be easily provided for the purpose of making the welding operation entirely automatic.

lhe front of back plate 9 is provided with a number of axially aligned bearing lugs 15 which, together with a sleeve 16 depending from the lower lug i5, serve as guides for a vertically movable tubular barrel I! and a metal rod i8 which projects from the upper end thereof. The rod l8 and a carbon electrode :9 are mounted axially of the barrel H so that they are in contact at about its center. The rod I8 may then serve, when actuated in a manner to be described subsequently, to feed the electrode is after it has burned or broken off.

By the use of a sufficiently long electrode 19 the rod [8 could be omited. For reasons of strength and wear resistance, however, it is preferable that the rod it be used.

The actuating means for the barrel i? may include a solenoid 2t adjustably secured to back plate 9 and having a vertically movable core 2! connected to the narrow end of a yoke 22. The yoke 22, as shown in Fig. 5, is disposed transversely of barrel I? and is pivoted at its wide end on a bolt 23 which extends forwardly from back plate 53 and serves as a fulcrum. Barrel i7 is provided at its upper end with an annular flange 24 so that it may be supported, but left free for rotation about its axis, by a pair of pins 25 which project inwardly from the center of yoke 22.

The barrel H is thus elevated when the ener gization of solenoid 26 causes it to attract its core 2i upwardly, with consequent upward pivot of the yoke 22 about fulcrum bolt 23.

Serving to hold the electrode l3, and thus the rod id, in the barrel l'. is a leaf spring 25 shown in Fig. 9 as mounted longitudinally of the barrel .l'i in a rectangular shaped groove 21 at the lower end thereof. The spring 26 is preferably hooked at its lower end to resiliently urge a segment 28, which fits into a corresponding recess ,in the barrel i7, against the electrode id. The

segment 28 is provided with an outer groove 29 cut to register with the groove 2'! in barrel l1, and an inner groove 33 which corresponds with the bore in barrel i7. Groove 33 is preferably :chamfered at its ends to allow easy insertion of the electrode i3 into the barrel i1.

In order to maintain a uniform arc length it is necessary that the electrode !9 be fed towards the work after it has burned or broken off. This may be done automatically by a feeding ratchet 3i positioned transversely of the rod 53 a short distance above the upper end of the barrel i'i.

Referring to Figs. 3 and 4, ratchet 3i preferably includes a horizontal arm 32 pivotally con- ;nected at one end to a stud 33 which projects from back plate 9, a rocker member 34 disposed adjacent rod i8 and hinged to the free end of arm 32,

and a flat spring 35 pinned at about its center to the underside of the rocker 34.

The spring 35 is apertured at one end to fit around rod l8 and is preferably bifurcated at the other end, in order to increase its resiliency, to form a short wide portion 36 and a long narrow portion 3?. Serving to maintain spring 35 in an oblique position, so that it binds with rod fi8, is a cap screw 38 which is threaded downiwar'dly through arm 32 and bears against the outer end of the long narrow portion 37 of spring 3'5. The. operation of the described construction is such that the rod i8 may move downwardly but not upwardly with respect to the spring 35.

In order to limit the upward and downward movements of the arm 32, upper and lower set screws 35 and 44 are threaded through corresponding lugs 4% which are mounted on the back plate 9. The arrangement of lugs 41 is such that when the arm 32 is in its lower position the short wide portion 3.5 of spring 35 is in engagement with the, lower set screw 46. Set screws 39 and 40 are adjusted to allow spring 35 to ride freely with rod 18 for a distance which is equal to the desired arc length.

Assuming that when the barrel I! is in its lower position the arm 32 is also in its lower position, upward movement of barrel I? for a distance equal to the arc length causes the arm 32 to contact the upper set screw 39. Further upward movement of barrel i1 causes the rod 3, and thus the electrode is, to feed downwardly through the barrel ll, since rod i8 is held stationary by the spring 35 as soon as the arm 32 contacts the upper set screw 39.

Subsequent lowering of the barrel I? for a distance equal to the arc length causes the short wide arm 35 of spring 35 to contact the lower set screw 40, tending to bend the spring 35 and thereby aid in releasin the rod 58. Upon additional lowering of barrel ii, the rod I-B feeds downwardly through the spring 35.

In constructions where the weight of the rod [8 is insufficient to cause it to feed downwardly through the spring 35 against the frictional resistance thereof, means may be provided to prevent the rod 18 from separating from the electrode i9 as the barrel I? is lowered. These means may take the form of a holding ratchet 42 disposed at the top surface of the barrel I! subjacent ratchet 3|.

The holding ratchet 42, as shown in Figs. 5 and 6, may comprise a suitable washer 43 mounted around rod 18 and resiliently held in oblique binding relation therewith by a circular spring 44. The spring 44 is anchored in an annular groove 45 at the top surface of barrel 1! and inclines upwardly to engage the washer 43.

Upward movement of the washer 43 is limited by a small angular stop 46 and a larger angular stop 47, both of which are integral with the flange 24 on the barrel [1. The small stop 46 is disposed with its horizontal portion slightly above the lower edge of washer 43, while the larger stop 41 is arranged diametrically opposite stop 46 with its horizontal portion above the elevated edge of washer 43.

The action of ratchet 42 is such that the rod I8 and thus electrode l9 may be fed downwardly with respect to the barrel H, but upward movement with respect thereto is positively prevented. Consequently, the rod l8 may not be held stationary, and thus separated from the electrode [9, as the barrel I! moves downwardly.

In addition to its function of keeping the electrode l9 and the rod I8 from separating, ratchet 42 aids in preventing the electrode i9 from being moved upwardly with respect to barrel I! as the electrode [9 strikes an obstruction such as the article to be welded.

The burning of the electrode 19 may be made uniform, with consequent increase of arc stability, by a ratchet 43 which operates to rotate the electrode l9 between each weld. Ratchet 48 is preferably mounted around barrel 17 so that it may be rotated with respect to the barrel 1!- when actuated in one direction, but may not be so rotated when actuated in the opposite direction.

Referring to Fig. 8, the ratchet 43 may comprise a generally annular member 49 from which a triangularly shaped portion 50 protrudes, a ball 5| arranged in a recess 52 which is cut in the inner edge of the member 49, and a compressed helical spring 53 disposed in a hole 54 which is bored through the triangular portion 50 of the member 49. V

The recess 52 is shaped with a narrow end and a wide end, so that the ball is jammed be.-

tween member 49' and the barrel i! when it is at the narrow end but. isv not thus jammed when it is at the wide end.

The hole 54 extends tangentially of the barrel 1! from the wide end of the recess 52 to a point adjacent the apex of the triangularly shaped portion 5c of the member 49. The helical spring the barrel i! since the ball 5.! tends to. move toward the wide end of the recess 52 and therefore does not jam between the barrel I1. and the. member 49.

Axial movement of the ratchet 38 with respect to the barrel I? is prevented by a pair of collars 56 secured to the barrel I1 and preferably disposed to hold the ratchet 4 midway between the two lower bearing lugs 15.

The ratchet 48 is actuated through a suitable linkage 5'! which connects the outer end of the triangular portion 50 of the member #9 with the lower end of an arm 58. Arm 58' extends downwardly from the front portion of the yoke 22, with which it is integral at the fulcrum bolt 23.

Energization of the solenoid as, with consequent counterclockwise movement of the. yoke 22 and the arm 58, causes the ratchet 48 and thus barrel ll to rotate in a counterclockwise direction. De-eneigization of the solenoid. 29 reverses these movements but, as previously described, the barrel I! does not rotate with the ratchet 48 as the ratchet 48 rotates in a clockwise direction.

By a suitably arranged ratchet the barrel l1 and thus the electrode [9 could be made to rotate in either a clockwise or counterclockwise direction, and upon either energization or de-energizas tion of solenoid 29. This however, is not critical, the important thing being that the electrode [9 be rotated slightly, in either direction, between each weld.

The electrode feed mechanism may be maintained in adjustment when the apparatus is not in use by a tongue 59 which is hinged to the back plate 9 so that it maybe swung between the lower bearing lug I5 and the lower collar 56. Tongue'59 operates to prevent the barrel 1'! from falling when the solenoid is de-energized and there is no support on which the electrode #9 may rest.

Electrical contact is made with the barrel I! by means of a brush 60 mounted on barrel H between the ratchet 48 and the center bearing lug IS. The brush 60 is shown in detail in Fig. 7 and preferably includes a rectangular band 6| provided with ears or the like to slidably support front and rear bronze contact blocks 62 and 83, respectively, the inner surfaces of the blocks being curved to afford close contact with the barrel I1.

Serving to bias the blocks 62 and 63 against the barrel I7 is a helical spring 64 arranged on a bronze rod 65 in a space between the rear contact block 63 and the rear of the band 6 l. The bronze rod 65 extends rearwardly from block 63 through an aperture in band GI and a vertical slot 66 in 6 the back plate 9, with the slot 56 permitting the brush to move vertically with the barrel I! but not to rotate with it.

In carrying out the electrical circuits, the end of rod is connected through a flexible lead 67 to the back plate 9, which in turn is connected to the negative terminal of a suitable direct current welding generator 68. The positive terminal of the generator 68 is connected via a normally open welding. current contact 69 of a relay coil 70 to theworktable 2.

The welding current circuit may then be completed from the positive terminal of generator 68 through contact 69, worktable 2, the article to be welded, electrode 19, barrel l1, brush so, lead 61, and back plate 9 to the negative terminal of generator 68. Insulation in the mountings of the grooved wheels 8 keeps the back plate 9 electrically separate from the worktable 2 and prevents the shorting of the generator 68.

The welding, current contact 69 is shunted by a relay coill-l having a normally open contact 12. Coil H is energized by the generator 68 when the electrode I9 is in contact with the article to be welded and the welding current contact 69 is open, since closing of the welding current contact 69 provides a short circuiting path which the current takes instead of flowing through the coil 1| The. relay system, which is preferably disposed in the cabinet I, may be energized through a master switch "It by 110 volt supply lines 74 and 75.

The coil 70 forms part of a series combination which also includes a contact it or a relay coil 11, contact '12 of the relay coil H, and a second contact 13. of relay coil ll, all of said contacts being of the normally open type. This series combination is connected across supply lines It and T5 and is. arranged so that current may flow from line 75 through coil 73, contact "i6, contact 12, and contact 18 to line M.

The solenoid Zilis connected across lines Mend 15 in series with a third contact 79 of the relay coil i1. Contact 19 is normally closed, so that solenoid 2G is normally energized and the barrel I! and electrode l9 normally maintained in elevated position.

Serving to shunt the contact 72 of relay coil H is a second contact 8% of the relay coil 10. A third contact 8! of relay coil it! is connected on one side to the solenoid 2e side of contact 79, and r)? the other side to the contact 12 side of contact The relay coil ll is connected between line '14 and one side of a normally closed contact 82 of a suitable time delay relay 83. The other side of contact 82 is connected via a normally open microswitch 86 to the line '55. The coil of the time delay relay 83 is connected on one side to line 14 and on the other side to the contact 82 side of the microswitch 84.

The time delay relay 23 is constructed with an adjustable dash pot or other means whereby the contact 82 will not open until a period of time, preferably about two or three seconds, after the closing of microswitch 84 has caused energization of the coil 85.

The microswitch 84 may be actuated in any suitable manner, for instance by the movements of the bar I2 which connects the piston II and the back plate 9. Accordingly, the microswitch 84 may be disposed in a small rigid box as shown in Fig. 11 as secured adjacent the connecting bar 12 onthe top surface of the cabinet I.

The upper side of the box 86-is apertured for insertion of a contact arm 81 which projects up.- wardly from the microswitch 8d. The arm 81 operates to close the microswitch 85 when engaged by the head of a bolt 88 which is threaded upwardly into a lug 89 on the connecting bar ill.

The bolt 88 also serves to engage the top of box 86 and thereby stop the downward movement of the connecting bar l2, back plate 9, and thus electrode I9. Bolt 88 is preferably adjusted to stop the above downward movement when the distance between the lower end of the electrode i9 and the article to be welded is equal to the desired arc length.

The operation of the welding apparatus is as follows: Assume that the back plate!) is in its upper position, with the electrode l9 above the article to be welded, and that the welding generator 68 has been started and the master switch [3 closed. Solenoid is thus energized, causing it to maintain the barrel H and electrode 19 in their elevated position with respect to the back plate 9, so that the tongue 59 may be swung away from the barrel [1.

If necessary, the operator then positions the electrode 49 in the barrel I! so that when back plate 9 is in its lower position, the distance between the lower end of the electrode I9 and the article to be welded is equal to the desired arc length. The operator also makes sure that the set screws 39 and M3 of the feeding ratchet 3! are adjusted to allow the fiat spring to ride freely with the rod [8 for a distance equal to the arc length, and that the horizontal arm 32 is in contact with the upper set screw 39.

The moving of the valve I3 to weld position r releases the air from the air cylinder Iii and permits the back plate 9, barrel ll, electrode it, etc., to fall until the head of bolt 88 engages the box 86. The contact arm 81 of microswitch B4 is then depressed, closing the switch 84, and the lower end of the electrode I9 is the arc length distance above the article to be welded.

The closing of microswitch 84 causes energization of both the time delay relay coil 85 and the relaycoil ll. Contacts 16 and 180i relay coil 11 then close, while contact 19 of relay coil ll opens. The contact 82 of the time delay relay 83 remains closed, however, since the dash pot operates to delay the eiiects of the energization of the coil 85. r

The opening of contact 19 de-energizes the solenoid 20, which releases the solenoid core 2| and allows the yoke 22, barrel l7, electrode l9, etc., to drop until the electrode l9 contacts the article to be welded.

This completes a direct current circuit from the generator 68 through the relay coil ii, causing the contact E2 of relay coil ll to close. A circuit is thereby completed from line 14 through contact 78, contact 32, contact 15, and relay coil 19 to line 15. Relay coil It is then energized, causing it to close its contacts 69, 80, and BI.

Contact 69, in closing, completes the main welding circuit and also by-passes and de-energizes coil H, which allows contact 1'2 to open. Energization of relay coil H! is nevertheless maintained through contact 80 of relay coil ill, with the circuit being traceable from line 14 through contact 18, contact 80, contact '56, and relay coil 10 to line '75.

The closing of contact 8| re-energizes the solenoid 20, since contact 18 is closed. The solenoid core 21 is then attracted upwardly, elevating yoke 22, barrel l7, rod l8, and electrode l9, and striking the arc. The are is maintained for the desired period, depending on the setting of the dash pot of the time delay relay 83, until the contact 82 opens and de-energizes relay coil 11.

De-energization of coil 11 causes its contacts 78 and 16 to open and contact 19 to close. The coil 10 is then de-energized and the welding current shut ofi, but solenoid 20 is energized through contact I9 and the electrode I9 is maintained in elevated position.

Current flowing through microswitch 84 keeps the time delay relay coil in energized condition and prevents contact 82 from closing and starting the cycle again.

The welder then moves the valve l3 to of! position, which admits compressed air into the cylinder I0 and elevates the back plate 9, barrel ll, etc., allowing the microswitch 84 to open. The apparatus is then ready for another welding cycle as soon as the operator adjusts or replaces the article to be welded.

If the electrode 19 has not burned or broken ofi during the first welding cycle, the feeding ratchet 3| will not operate during the next welding cycle to cause the rod l8 and thus the electrode IE to feed downwardly through the barrel N. This is because the spring 35 and horizontal arm 32 of ratchet 3! will ride with the rod 18 and Will not be limited in their movement by either of set screws 39 or 40, the apparatus having been adjusted, as previously described, to accomplish this result.

The breaking or burning ofi of the electrode l9 during one cycle of welding causes the feeding ratchet 3! to feed the rod l8 and electrode l9 downwardly through the barrel l'l during the following welding cycle, and thus keep the arc length constant. When the back plate 9 is in its lower position after the operator turns the valve l3 to weld position, de-energization of the solenoid 20 allows the yoke 22, barrel ll, rod [8, and electrode 19 to fall until the electrode l9 strikes the article to be welded.

For the first part, equal to the arc length, of this downward movement, the spring 35 of ratchet 3! will ride downwardly with the rod I8 and the short wide portion 36 of spring 35 will engage the lower set screw 48. For the remaining downward movement, equal to the amount of carbon burned on, the rod It will feed downwardly through the spring 35, with the holding ratchet 42 preventing the rod I8 from separating from the electrode l9.

Subsequent energization of the solenoid 20 to strike the arc causes the barrel l1, rod [8, and electrode E9 to be elevated for a distance equal to the desired arc length, until the horizontal arm 32 of ratchet 3! engages the upper set screw 39. The barrel 11 then continues to move upwardly for the remaining distance, equal to the amount of carbon burned oil, until the solenoid core 2| and the barrel I? are in their initial postitions. The rod l8 and electrode I9, however, are held stationary by the spring 35 and are thus fed through the barrel l? to maintain the desired arc length.

The operation of the ratchetfit, which rotates the barrel ii and electrode l9 between each weld, was described in connection with the detailed description of that element.

Various embodiments of the invention may be employed within the scope of the accompanying claims.

I claim:

1. In an arc welding apparatus adapted for use with a carbon electrode, a support, means movably mounted on said support to hold said electrode. means carried by said support to effect movement of said holding means from :an initial position until said electrode engages the article to be :welded and to subsequentlyreturn said holding means to said initial position, and means operably associated with said electrode to permit said electrode to move with said holding means until said electrode engages the article to be welded and to return with said holding means for a predetermined distance equal to the desired arc length, wherebysaid electrode feeds with respect to said holding means when the distance moved by s""'d holding means on said return movem nt is greater than said predetermined arc length but does not so feed when the distance moved said holding means on said return movement is equal to said predetermined arc length.

2. 'In an arc welding apparatus adapted f or use with a carbon electrode, asupport, means inov ably mounted on said su port to hold said electrode, means carried b; said support to effect movement of said holding means from an initial position until said move. cut is stopped by the engagement of said electrode with the article'to be welded and to subsequently return said holding means to said initial position, and a movable member operably associated with said electrode. said member beirr adapted to permit feeding movement of said electrode relative thereto but to restrain said electrode against return movement relative thereto, and stop means to limit the movements of said member to a predetermined distance equal to the desired-arc length.

3. In a device of the class described adapted for use with a carbon electrode, a support, means movably mounted on said support to resiliently hold said electrode, a solenoid and a solenoid core carried by said support and operably associated with said holding means to return said holdi g means to an initial position after said. means has fallen from said initial position to the position assumed upon engagement of said electrode with the article to be welded, a rod mounted in said holding means in axial alignment with said electrode to feed the same, a ratchet member movably mounted onsaid support and adapted to allow downward movement of said rod through said ratchet member but to prevent opt-vain movement of said rod therethrough, upper and lower stops arranged on said support to limit the movemenu; of said ratchet member to a predetermined distance equal to the desired arc length.

4. In an arc welding apparatus adapted for use with a carbon electrode, a support, means mov ably mounted. on said support .to hold said electrode, means carried. by said support to effect movementof holding means from an initial position until said movement is stopped the engagement of said electrode with the article to be welded and to subsequcitly return holding means to said initial position, a feeding ratchet movably mounted on said support and operably associated with said electrode, said ratchet including a binding member and stops disposed on said support to limit the movements of said. binding member to predetermined distance equal to the desired arc length, and a holding ratchet mounted on said holding means to prevent said electrode from moving upwardiy therethrough, whereby said electrode moves with said holding means until said electrode engages the article to be welded and returns with said holding means until said electrode is separated from the article to be welded for a distance equal to predetermined arc length.

5. In an arc welding apparatus adapted for use with a carbon electrode, a support, means movably mounted on said-support to hold saidelectrode, means carried by said support to efieot movement of said holding means from an initial position until said movement is stopped by the engagement of said electrode with the article to be welded and to subsequently return said holding means to said initial position, a feeding ratchet movably mounted on said support and operably associated with said electrode, said ratchet including a binding member and stops disposed on said support to limit the movements of said binding member to a predetermined distance equal to the desiredarc length, and a rotating ratchet adapted to intermittently rotate said electrode to promote uniformity of the burning thereof, whereby said electrode moves with said holding means until said electrode engages the article to be welded and returns with said holding means until said electrode is separated from the article to be welded for a distance equal to said predetermined arc length, one of said movements being accompanied by rotation of said electrode.

6. In an arc welding apparatus adapted to.

weld with a carbon electrode, a frame structure, a movable support mounted in said frame, means carried by said frame to effect movement of said support to upper and lower positions, means movably mounted on said support to hold said electrode, means carried by said support to effect movement of said holding means from an initial position until said electrode engages the article to be welded and to subsequently return said holding means to said initial position, and means mounted on said support and operabiy associated with said electrode to prevent said electrode from returning with said holding means for a distancegreater than the desired arc length.

7. In a device of the class described adapted for means movably mounted on said support andoperably associated with said electrode to permit said electrode to move with said holding means until said electrode engages the article to be welded and to return with said holding means for a predetermined distance equal to the desired arc length.

8. In a device of the class described adapted for use with a carbon electrode, a stationary frame structure, a movable support mounted in said frame, means carried by said frame to effect movement of said support to upper and lower positions, means movably mounted on said support to hold said electrode, a solenoid and solenoid core carried by said support and connected to said holding means, said solenoid and solenoid core being operable when said support is in its lower position to return said holding means to an initial position after the same has fallen therefrom to a position assumed upon engagement of said electrode with the article to be welded, a

binding member operably associated with said electrode to allow downward movement of said electrode with respect to said binding member but to prevent upward movement with respect use with a carbon electrode, a frame structure, a movable support mounted in said frame,

acseus'za thereto, and stops disposed on said support to limit the movements of said binding member to a predetermined distance equal to the desired arc length.

9. Inia device of the class described adapted for use with a carbon electrode, a frame structure, a support movably mounted in said frame, a cylinder supported by said frame, a piston mounted in said cylinder and connected to said support to effect vertical movement thereof, a stop disposed on said frame to arrest the downward movement of said support, means movably mounted on said support to hold said electrode, a solenoid and solenoid core carried by said support and connected to said holding means, said solenoid and solenoid core being operable when said support is in its lower position to return said holding means to an initial position after the same has fallen therefrom to a position assumedupon engagement of said electrode with the article to be welded, a member operably associated with said electrode to allow downward movement of said electrode with respect to said member but to prevent upward movement with respect thereto, and stops disposed on said support to limit the movements of said member to a predetermined distance equal to the desired arc length.

10. In a device of the class described adapted for use with a carbon electrode, a stationary frame structure, a movable support mounted in said frame, means carried by said frame to effect movement of said support to upper and lower positions, means movably mounted on said support to hold said electrode, means carried by said support to actuate said holding means, said actuating means being operable when said support is in its lower position to return said holding means to an initial position after the same has moved therefrom to a position assumed upon engagement of said electrode with the article to be welded, a movable member operably associated with said electrode to allow downward movement of said electrode with respect to said member but 7 to prevent upward movement with respect thereto, stops disposed on said support to limit the movement of said binding member to a predetermined distance equal to the desired arc length, and. a holding ratchet mounted on said holding means to prevent said electrode from moving upwardly therethrough.

11. In a device of the class described adapted for use with a carbon electrode, a stationary frame structure, a movable support mounted in said frame, means carried by said frame to effect movement of said support to upper and lower positions, means movably mounted on said support to hold said electrode, means carried by said support to actuate said holding means, said actuating means being operable when said support is in its lower position to return said holding means to an initial position after the same has moved therefrom to a position assumed upon engagement of said electrode with the article to be welded, a feeding ratchet mounted on said support and operably associated with said electrode, said ratchet including a binding member adapted to prevent upward movement of said electrode relative thereto and stops disposed on said support to limit the movement of said binding member to a predetermined distance equal to the desired arc length, and a rotating ratchet actuated by said actuating means and disposed to intermittently rotate said electrode to promote uniformity of the burning thereof.

12. In an arc welding apparatus adapted to weld with a vertically movable carbon electrode, a vertically movable support, electrode holding means movably mounted on said support, means carried by said support to actuate said holding means, said actuating means being operable to effect lowering of said holding means until said electrode engages the article to be welded and to subsequently elevate said holding means and electrode to strike the arc, a welding current circuit through said electrode, a welding current relay having a contact in said welding current circuit, and a time delay relay system actuated by movement of said support to its lower position and electrically connected with said actuating means and said welding current relay to controlthe same to cause a weld of predetermined duration to be made.

13. In an arc welding apparatus adapted to weld with a carbon electrode, a frame structure, a support movably mounted in said frame, means carried by said frame to effect movement of said support to upper and lower positions, electrode holding means mounted on said support for vertical movement with respect thereto, means carried by said support to actuate said holding means,

said actuatin means being operable when said support is in its lower position to effect movement of said holding means until said movement is stopped by the engagement of said electrode with the article to be welded and to subsequently return said holding means to its initial position, a welding current circuit including said electrode, a welding current relay having a contact in said welding current circuit, and a relay system actuated by the movement of said support to its lower position and electrically connected with said actuating means and said welding current relay to control the same.

14. In an arc welding apparatus adapted to Weld with a carbon electrode, a vertically movable support, electrode holding means movably mounted on said support, means carried by said support to actuate said holding means, said actu-.

the article to be welded and to subsequently elevate said holding means to its initial position, means movably mounted on said support and operably associated with said electrode to prevent the same from being elevated with said holding means for a distance greater than the desired arc length, a welding current circuit including said electrode, a welding current relay having a contact in said welding current circuit, and a time delay relay system actuated by movement of said support to its lower position and electrically connected with said actuating means and said welding current relay to control the same to cause a weld of predetermined duration to be made,

15. In an arc welding apparatus adapted to weld with a carbon electrode, a frame structure, a support movably mounted in said frame, means carried by said frame to eifect movement of said support to upper and lower positions, electrode holding means mounted on said support for vertical movement with respect thereto, means carried by said support to actuate said holding means, said actuating means being operable when said support is in its lower position to effect movement of said holding means until said movement is stopped by the engagement of said electrode with the article to be welded and to subsequently return said holding means to its initial position, feeding meansmovably mounted on said support and operably associated with said electrode, said feeding mean including a member adapted to allow downward movement of said electrode with respect to said member but to prevent upward movement of said electrode with respect thereto, a welding current circuit including said electrode, a welding current relay having a contact in said welding current circuit, and a relay system actuated by the movement of said support to its lower position and electrically connected with said actuating means and said welding current relay to control the same.

16. In an arc welding apparatus adapted to weld with a carbon electrode, a frame structure, a movable support mounted in frame, means carried by said frame to effect movement of said support to upper and lower positions, means movebly mounted on said support to hold said electrode, actuating means carried by said support to effect movement of said holding means from an initial position until said electrode engage the article to be welded and to subsequently return said holding means to said initial position, means mounted on said support and operably associated with said electrode to prevent said electrode from returning with said holding means for a distance greater than the desired arc length, a welding current circuit includin said electrode, a welding current relay having a contact in said welding current circuit, and a time delay relay system electrically connected with said actuating means and said welding current relay to control the same to cause a weld of predetermined duration to be made.

17. In a relay system adapted to be employed with an arc welding apparatus having a welding circuit connected to a source of welding current, a carbon electrode in said welding circuit, and electrically operated means to effect movement of said electrode, a starting relay coil having a contact in the circuit of said electrode moving means to actuate said mean and thereby effect movement of said electrode until the same engages the article to be welded, a welding current relay coil having a welding current contact in said welding circuit, a relay coil connected in shunt with said welding current contact and having a contact in the circuit of said welding current relay coil to energize said coil when said electrode engages the article to be Welded and thus cause the closing of said welding current contact to complete said welding circuit, a holding circuit connected to maintain the energization of said welding current relay coil when said shunt relay coil is vie-energized by the closing of said welding current contact, a second contact of said welding current relay coil connected in the circuit of said electrode moving means in parallel with said starting relay contact to actuate said electrode moving means and cause said electrode to be separated from the article to be Welded to strike the arc, and time delay means to open said Welding circuit at the end of a predetermined period after the closing thereof.

18. In an arc welding apparatus for automatically establishing and breakin a welding are in predetermined relation to effect are spotting, comprising an electrode, a solenoid normally encrgized to support the electrode a predetermined arc length distance above the work, trip means to open the circuit of said solenoid and thereby drop the electrode into contact with the work and close the welding circuit, a pair of relays energized respectively by said trip means and the closing or" the welding circuit and having their contacts in series to energize a third relay operable to shunt said relay closed by the welding circuit and to provide a substitute closing circuit for said third relay, said th rd relay additionally energizing the said solenoid to effect striking of the arc between the electrode and a work piece, and time delay means to open the circuit or" the relay previously energized by said trip means to deenergize said third relay and thereby extinguish the arc with the electrode held in raised position by said normally energized solenoid.

19. An arc welding apparatus for automatically establishing and breaking a welding arc in repeated succession and having a welding head adapted to strike and maintain an arc between an electrode and a work piece disposed in a position of relative inaccessibility, comprising a movable support for the welding head, means to move the support to and from operative position for said welding head, an electric circuit for said welding head adapted to effect automatic operation of the same for a predetermined work cycle, switch means in said circuit and disposed in the path of movement of said support to be actuated to initiate the welding cycle by movement of the support to position the welding head operatively to the work piece, and time delay switch means in said circuit responsive to said initiation of the welding cycle to terminate the same.

PERRY ANDERSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,493,440 Streson May 6, 1924 1,930,290 Streson Oct, 10, 1933 2,460,990 Kratz et al Feb. 8, 1949 2,461,798 Anderson Feb. 15, 1949 2,550,495 Pilia Apr. 24, 1951 

